In a typical sound source detection apparatus, peripheral sounds are collected respectively by a plurality of sound collectors, and the existence, direction, and so on of a sound source (travel sound from a vehicle, for example) is detected using a cross-correlation between the sounds collected by the plurality of sound collectors. In an apparatus described in Patent Document 1, acoustic signals output respectively by a plurality of microphones disposed at predetermined intervals are converted into corrected acoustic signals by removing frequency components in a low frequency band and a high frequency band respectively therefrom using a band pass filter, whereupon a power of a predetermined frequency band in which features of vehicle travel sound appear is calculated from the corrected acoustic signals. When the power level is higher than a predetermined value, it is determined that an approaching vehicle exists. Further, the corrected acoustic signals are converted into noise-reduced signals by removing an unnecessary noise component therefrom, whereupon a cross-correlation between the noise-reduced signals from the plurality of microphones is calculated. An approach direction of the approaching vehicle is then identified from an arrival time difference occurring when the cross-correlation takes a maximum value.
Patent Document 1: Japanese Utility Model Application Publication No. 5-92767
Patent Document 2: Japanese Patent Application Publication No. 8-202999
Patent Document 3: Japanese Patent Application Publication No. 60-151522